Microplastics in stair-step moss and lake water on Baffin Island, Nunavut, reflect a local source component

Microplastics (MPs) are contaminants of emerging Arctic concern due to their adverse effects on ecosystems, yet lake water and shorelands on Baffin Island, Nunavut, remain understudied for contamination. To address this knowledge gap, we investigated microplastic pollution in moss, water, and lakeshore surface sediment collected from nine lakes east and upwind of Iqaluit, Nunavut, and ten lakes north and downwind of Iqaluit. Stair-step moss (Hylocomium splendens) was used as a proxy for atmospheric deposition of MPs into the lake areas, whereas water and sediment were sampled to understand the depositional fate of MPs. The average microplastic concentration in lake water east of Iqaluit was statistically greater than the average abundance in the northern lakes. As distance from the community increased, both microplastic count concentrations in water and mass concentrations in moss decreased, suggesting a local source input from Iqaluit. A positive correlation between microplastic abundances in lake water and stair-step moss suggested the lakes received atmospheric MPs and supports the viability of using moss as a proxy for atmospheric deposition. The results of our study indicate that, in addition to oft-reported long-range transport of MPs to the Arctic, local inputs also contribute to the microplastic burden in northern, remote regions.